Whisk first six ingredients. Place in a 1-qt. jar; top with cranberries. In a small plastic bag, combine streusel ingredients. Add to jar; cover. Store in a cool dry place up to 3 months.
To prepare muffins: Preheat oven to 375°. Place muffin mix in a large bowl. In a small bowl, whisk egg, water and canola oil until blended. Add to muffin mix; stir just until moistened. Fill paper or foil-lined muffin cups three-fourths full. Combine streusel with melted butter. Sprinkle evenly over muffin cups.
Bake until a toothpick inserted in center comes out clean, 15-18 minutes. Cool 5 minutes before removing from pan to a wire rack. Serve warm.